Endocrine - Adrenal hormones Flashcards
Name the 3 layers of the cortex of the adrenal medulla from outside to inside
- zona glomerulosa
- zona fasciculata
- zona reticularis
what type (chemical category) of hormones does the cortex and medulla of the adrenal cortex secrete?
The cortex releases steroid hormones and the medulla releases catecholamines
what are the three categories of corticosteroids that the adrenal cortex secrete?
- mineralcorticoids
- glucocorticoids
- sex hormones
aside from the inner layers of the adrenal cortex, what other place produces sex hormones?
in the gonads in much higher abundance.
what stimulated the release of cortisol from the adrenal medulla?
ACTH from the anterior pituitary
Why can’t steroid hormones move freely in the blood? What are they bound to?
steroid hormones are hydrophobic and so must be transported by proteins. Cortisol is transported by transcortin and the others by albumin
TRUE or FALSE: Cortisol is essential for life. Why or why not?
TRUE; important direct effects on intermediary metabolism of carbohydrate, protein and lipid
what are the effects of cortisol?
- hepatic gluconeogenesis (amino acids into carbohydrates)
- increases breakdown of lipids
- increases protein breakdown (muscles)
- increases the amount of glucose available to the brain by inhibiting utilization by other tissues
What does the ‘permissive action of cortisol’ mean?
This means that there is an amount of cortisol that is required to allow for other processes to occur such as its effect on catecholamines
what effects does cortisol have at pharmacological concentrations that it doesn’t have at normal concentrations?
- immunosuppresion
2. anti-inflammatory
using glucocorticoids for long term use can have several consequences. What are they?
- loss of bone mass
- impaired body’s defence against infections
- atrophy of the adrenal (negative feedback on pituitary-adrenal axis)
- hyperglycemia
what negative consequences can occur when taking synthetic glucocorticoids?
- cause negative feedback on anterior pituitary which causes atrophy of corticotropes because no ACTH is required
- atrophy of adrenal cortex because of lack of stimulation by ACTH
- low levels of cortisol, aldosterone and DHEA production
what does aldosterone do?
controls body fluid volume by increasing sodium reabsorption by the kidneys
What stimulates aldosterone secretion?
- activation of renin-angiotensin system in response to decreased blood pressure , low Na and high plasma K
- ACTH has only a minor role
What does DHEA stand for?
Dehydroepiandrosterone